Engine rebuilding typically requires that the valve seats be resurfaced either by cutting or grinding new surfaces. For this purpose, the cylinder head is typically mounted in a cradle which can be maneuvered while supported on a air cushion. An example of such apparatus, trademarked "Winona", is made by Winona Van Norman Machine Company, 4730 West Highway 61, Winona, Minn. 55987.
The cutting tool used to resurface a valve seat is typically driven by a motor through a rigid connection between the cutting tool and the motor. The use of a rigid tool connection requires that each valve stem guide hole be leveled prior to resurfacing the corresponding valve seat. A rigid tool connection also requires that the axis of the drive chuck be held in precise alignment with the axis of the valve stem guide hole during resurfacing. By "leveling" is meant that the axis of the guide hole is brought into a true vertical position when the plane perpendicular to the axis of the guide hole is "level" or horizontal. Thus, it would be desirable to provide a method and apparatus enabling the valve seat to be resurfaced with a minimum need for leveling of the guide holes. So far as applicant is aware, a practical non-rigid-type connection has never been known to be used between the drive motor and the cutting tool to eliminate the need for having to level each guide hole for each valve seat cutting operation. More specifically, so far as applicant is aware, it has not been known to use a constant velocity universal joint drive connection in lieu of the conventional rigid drive.